The invention relates to a turbomachine having a seal device as described in detail below.
For sealing out air at annular gaps between adjacent static hot gas guides of turbomachines in the flow direction, such as the stationary gas turbines of aircraft engines, segmented sealing plates are frequently used, which are pressurized during operation by a differential pressure on component-side sealing edges or sealing surfaces. In order to equilibrate displacements of the sealing edges relative to one another resulting from thermal expansion, engine vibrations, and the like, the sealing plates are frequently mounted tippable on at least one component of the hot gas guides. Since at the beginning, during startup of the turbomachine from the shutdown state, the differential pressure can build up, it is necessary that the sealing plate already represents an obstacle to the flow of air and develops its sealing effect, even without a pressure load. For this purpose, the sealing plates are pressed against the sealing edges by springs in the shutdown state. During operation, the springs follow the displacement of the components relative to one another, which is impressed by the environment. Now if, in addition to thermal loads, the springs are subjected to high expansions due to large relative displacements, their material can begin to creep. The springs lose their prestressing action, so that during the startup of the turbomachine, the sealing plates can no longer tightly press against the sealing edges.
A turbomachine with a seal device for sealing a gap between two stator components is shown in U.S. Pat. No. 6,988,369 B2; it has a segmented sealing element for mounting or holding it on one of the components and for bridging the gap, and a prestressing element for pressing the sealing element against a sealing edge of the stator components in each case. The prestressing element is attached to the stator component on the mounting side. The sealing edge of the stator component on the mounting side is next to the mounting and the sealing edge of the stator component free of the mounting is far from the mounting. The sealing edge next to the mounting is disposed between the mounting and the sealing edge far from the mounting, whereby the prestressing element engages on the back relative to the sealing edges, between the sealing edges on the sealing element near the sealing edge next to the mounting and remote from the sealing edge far from the mounting. The prestressing element is V-shaped and has a support leg, by which it is applied to the stator component on the mounting side. When the prestressing element is compressed as a consequence of a displacement of the sealing edges relative to one another, the support leg of the prestressing element tends to lift off the mounting-side stator component.
A comparative seal device is shown in EP 1 156 188 A2. A prestressing element is designed as a U-shaped leaf spring and is joined by one of its end segments in a fixed manner with a stator component on the mounting side. Its other end segment engages at the sealing plate. Fixing the prestressing spring at the component on the mounting side, however, is a complicated procedure.
From DE 40 06 498 A1 and U.S. Pat. No. 8,257,028 B2, it is also known to design the prestressing elements as flat spiral springs that are mounted directly on a mounting bolt for the sealing elements.
Other turbomachines with seal devices are shown in U.S. Pat. No. 6,464,457 B1, U.S. Pat. No. 7,040,098 B2, U.S. Pat. No. 8,459,041 B2, U.S. Pat. No. 5,797,723, DE 10 2006 017 377 A1, US 2012/0107122 A1 and in U.S. Pat. No. 6,431,555 B1.